1. Field of the Invention
The present invention relates to an apparatus for adjusting a tie rod by using an open end wrench, the tie rod being built in a steering mechanism of a vehicle such as a motor vehicle.
2. Description of the Related Art
A conventional steering mechanism for a motor vehicle has built therein, as shown in FIG. 19, a tie rod C which transmits the movement of a relay rod A which moves in interlocking with a steering handle to a knuckle arm B which rotatably supports a wheel. The tie rod C is made up of a rod main body C1 which is connected to the relay rod A through a ball joint A1, and a rod end C2 which is connected to the knuckle arm B through a ball joint B1. The end portion of the rod main body C1 is threaded into the rod end C2. By changing the depth of this threaded connection, the length of the tie rod C is varied, whereby the toe of the wheels can be adjusted. In the figure, reference characters C3 denote a tool engaging portion which is hexagonal in cross section and which is formed in the rod main body C1. Reference characters C4 denote a lock nut which prevents the rod main body C1 from rotating.
As an apparatus for adjusting this kind of tie rod by using an open end wrench which has at its top end a rod rotating portion for rotating the rod main body in the normal direction of rotation or in the reverse direction of rotation by engaging it with the tool engaging portion C3, there are known apparatuses in Japanese Published Unexamined Patent Application Nos. 289770/1989 and 295766/1989. These apparatuses are each provided with a carriage which vertically moves an open end wrench toward, and away from, a tie rod from a lower side of the vehicle which stays at a predetermined position. The open end wrench is supported on the carriage through a supporting mechanism which has a freedom of four axes so that the open end wrench can be moved in the vehicle width direction and vehicle longitudinal direction, tilted in the vehicle width direction, and rotated about an axis which extends in the longitudinal direction of the open end wrench.
According to this arrangement, the open end wrench is moved in the vehicle width direction and the vehicle longitudinal direction depending on the deviation in position of the tie rod in the vehicle width direction and in the vehicle longitudinal direction. Further, depending on the tilting of the tie rod in the vehicle longitudinal direction, the open end wrench is rotated about a vertical axis of the open end wrench and, depending on the tilting of the tie rod in the vertical direction, the open end wrench is tilted in the vehicle width direction. By these operations, the rod rotating portion at the top end of the open end wrench is engaged with the tool engaging portion so that the axis of rotation of the rod rotating portion coincides with the axial line of the rod main body of the tie rod. By the rotation of the rod rotating portion, the rod main body is rotated to thereby adjust the length of the tie rod.
Further, in this prior art, that tilting member of the supporting mechanism which extends in the vehicle width direction is constituted such that the open end wrench is tiltable in the vehicle width direction with a lower supporting shaft which is lower than the open end wrench serving as a fulcrum.
In the above-described conventional apparatus, when the open end wrench is tilted in the vehicle width direction by the movement of the tilting member, the top end of the open end wrench largely deviates in the vehicle width direction. In order to correct this deviation, it becomes necessary to largely move the open end wrench in the vehicle width direction. There is therefore a disadvantage in that the positioning work of the open end wrench relative to the tie rod becomes troublesome.
In view of the above points, the present invention has an object of providing an apparatus for adjusting a tie rod in which the positioning of the open end wrench relative to the tie rod can be made easily.